U.S. patent number 10,132,234 [Application Number 15/342,320] was granted by the patent office on 2018-11-20 for method and system for controlling turbocharger of vehicle.
This patent grant is currently assigned to HYUNDAI MOTOR COMPANY. The grantee listed for this patent is HYUNDAI MOTOR COMPANY. Invention is credited to Hyun Kim.
United States Patent |
10,132,234 |
Kim |
November 20, 2018 |
Method and system for controlling turbocharger of vehicle
Abstract
A method of controlling a turbocharger of a vehicle includes
determining, by a controller, a target boost pressure of intake air
of a plurality of turbochargers according to one or more vehicle
driving conditions, and determining target opening ratios of a
plurality of wastegates respectively provided in the plurality of
turbochargers, according to the target boost pressure, determining,
by the controller, whether or not a current opening ratio detected
by an opening ratio sensor of any one wastegate of the plurality of
wastegates is lower than the target opening ratio of the associated
wastegate by a reference value, and limiting, by the controller, a
maximum rpm of the turbocharger having the associated wastegate
when it is determined that the current opening ratio of the
associated wastegate is lower than the target opening ratio by the
reference value.
Inventors: |
Kim; Hyun (Hwaseong-si,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
HYUNDAI MOTOR COMPANY |
Seoul |
N/A |
KR |
|
|
Assignee: |
HYUNDAI MOTOR COMPANY (Seoul,
KR)
|
Family
ID: |
60328067 |
Appl.
No.: |
15/342,320 |
Filed: |
November 3, 2016 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20170350311 A1 |
Dec 7, 2017 |
|
Foreign Application Priority Data
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|
|
|
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Jun 7, 2016 [KR] |
|
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10-2016-0070498 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02B
37/007 (20130101); F02B 37/18 (20130101); F02B
37/001 (20130101); F02D 41/0007 (20130101); F02D
2200/0406 (20130101); Y02T 10/12 (20130101); Y02T
10/144 (20130101) |
Current International
Class: |
F02B
37/18 (20060101); F02B 37/007 (20060101); F02D
41/00 (20060101); F02B 37/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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H07-293302 |
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Nov 1995 |
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JP |
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2008-095587 |
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Apr 2008 |
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JP |
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2010-059851 |
|
Mar 2010 |
|
JP |
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2014-101813 |
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Jun 2014 |
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JP |
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2015-178809 |
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Oct 2015 |
|
JP |
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2015-209789 |
|
Nov 2015 |
|
JP |
|
10-2004-0034760 |
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Apr 2004 |
|
KR |
|
10-2011-0060934 |
|
Jun 2011 |
|
KR |
|
10-1552061 |
|
Sep 2015 |
|
KR |
|
2010/039596 |
|
Apr 2010 |
|
WO |
|
Primary Examiner: Maines; Patrick
Attorney, Agent or Firm: McDermott Will & Emery LLP
Claims
What is claimed is:
1. A method of controlling a turbocharger of a vehicle, the method
comprising: determining, by a controller, a target boost pressure
of intake air of a plurality of turbochargers according to one or
more vehicle driving conditions, and determining target opening
ratios of a plurality of wastegates respectively provided in the
plurality of turbochargers, according to the target boost pressure;
determining, by the controller, whether or not a current opening
ratio detected by an opening ratio sensor of any one wastegate of
the plurality of wastegates is lower than the target opening ratio
of the associated wastegate by a reference value; and limiting, by
the controller, a maximum rpm of the turbocharger having the
associated wastegate when it is determined that the current opening
ratio of the associated wastegate is lower than the target opening
ratio by the reference value.
2. The method of claim 1, wherein the reference value is pre-set
for each of the plurality of wastegates and is stored in the
controller.
3. The method of claim 2, wherein the reference value is pre-set in
such a way that reference values of the respective wastegates are
individually determined in consideration of critical rpms of the
turbochargers having the respective wastegates.
4. The method of claim 1, wherein the controller limits the maximum
rpm of the turbocharger having the associated wastegate when it is
determined that a current boost pressure of intake air is equal to
or lower than the target boost pressure and the current opening
ratio of the associated wastegate is lower than the target opening
ratio by the reference value.
5. The method of claim 1, wherein the controller limits the maximum
rpm of at least one turbocharger including the turbocharger having
the wastegate of which the current opening ratio is lower than the
target opening ratio by the reference value.
6. The method of claim 1, wherein the controller limits the maximum
rpm of the turbocharger by limiting the target boost pressure.
7. The method of claim 1, wherein the controller controls the
plurality of wastegates using a data map in which the target
opening ratios of the plurality of wastegates are pre-set according
to the target boost pressure of intake air.
8. A system for controlling a turbocharger of a vehicle, the system
comprising: a plurality of turbochargers; a plurality of wastegates
respectively provided in the turbochargers and controlling flow
rates of exhaust gases passing through the turbochargers; a
plurality of opening ratio sensors provided at the respective
wastegates and measuring opening ratios of the wastegates; a boost
pressure sensor provided on an intake air flow line at a location
in a downstream of the plurality of turbochargers and detecting a
current boost pressure of intake air; and a controller that sets a
target boost pressure of intake air of the plurality of
turbochargers according to vehicle driving conditions, sets target
opening ratios of the plurality of wastegates according to the
target boost pressure, determines whether or not a current opening
ratio detected by an opening ratio sensor of any one wastegate of
the plurality of wastegates is lower than the target opening ratio
of the associated wastegate by a reference value, limits a maximum
rpm of the turbocharger having the associated wastegate when it is
determined that the current opening ratio is lower than the target
opening ratio by the reference value.
Description
CROSS REFERENCE TO RELATED APPLICATION
The present application claims the benefit of priority to Korean
Patent Application No. 10-2016-0070498, filed Jun. 7, 2016 with the
Korean Intellectual Property Office, the entire contents of which
is incorporated herein for all purposes by this reference.
TECHNICAL FIELD
The present disclosure relates to a turbocharger that functions to
increase an intake air volume by using the flow energy of engine
exhaust.
BACKGROUND
In a vehicle provided with a turbocharger, a wastegate may be
provided in the turbocharger so as to control the load acting on a
turbine of the turbocharger by enabling bypassing by exhaust gases
flowing to the turbocharger. In the related art, the wastegate may
be configured as a pneumatically controlled wastegate or as an
electronically controlled wastegate.
Particularly, the electronically controlled wastegate can perform
precise control for the opening ratio of the wastegate, thereby
functioning to control an operation of the turbocharger by
controlling the flow rate of exhaust gases flowing into the
turbine, thus controlling turbine rpm, intake air boost pressure,
etc.
Exhaust gases passing through both the turbine and the wastegate of
the turbocharger may include various impurities. The impurities may
easily adhere to the wastegate and may cause a wastegate to cease
functioning properly, so a malfunction of the turbocharger in which
the opening ratio of the wastegate fails to reach a target opening
ratio may occur.
Particularly, when the opening ratio of the wastegate fails to
reach the target opening ratio during high speed driving of a
vehicle, the turbine rpm may excessively increase and this may
cause adverse effects of the turbine. Thus, to realize an efficient
operation of the turbocharger, it is advantageous to appropriately
control the wastegate based on a correct understanding of the
operation of the wastegate.
The foregoing is intended merely to aid in the understanding of the
background of the present disclosure, and is not intended to mean
that the present disclosure falls within the purview of the related
art that is already known to those skilled in the art.
SUMMARY
Accordingly, the present disclosure has been made keeping in mind
the above problems occurring in the related art, and the present
disclosure is intended to propose a technique capable of
efficiently preventing breakage of a turbocharger caused by a
malfunction of a wastegate of the turbocharger based on correct and
efficient determination of the malfunction of the wastegate.
According to one aspect of the present disclosure, there is
provided a method of controlling a turbocharger of a vehicle, the
method including: determining, by a controller, a target boost
pressure of intake air of a plurality of turbochargers according to
one or more vehicle driving conditions, and determining target
opening ratios of a plurality of wastegates respectively provided
in the plurality of turbochargers, according to the target boost
pressure; determining, by the controller, whether or not a current
opening ratio detected by an opening ratio sensor of any one
wastegate of the plurality of wastegates is lower than the target
opening ratio of the associated wastegate by a reference value; and
limiting, by the controller, a maximum rpm of the turbocharger
having the associated wastegate when it is determined that the
current opening ratio of the associated wastegate is lower than the
target opening ratio by the reference value.
The reference value may be pre-set for each of the plurality of
wastegates and is stored in the controller.
The reference value may be pre-set in such a way that reference
values of the respective wastegates are individually determined in
consideration of critical rpms of the turbochargers having the
respective wastegates.
In embodiments of the method, the controller limits the maximum rpm
of the turbocharger having the associated wastegate when it is
determined that a current boost pressure of intake air is equal to
or lower than the target boost pressure and the current opening
ratio of the associated wastegate is lower than the target opening
ratio by the reference value.
In the method, the controller limits the maximum rpm of at least
one turbocharger having the wastegate of which the current opening
ratio is lower than the target opening ratio by the reference
value.
In the method, the controller limits the maximum rpm of the
turbocharger by limiting the target boost pressure.
In the method, the controller controls the plurality of wastegates
using a data map in which the target opening ratios of the
plurality of wastegates are pre-set according to the target boost
pressure of intake air.
According to another aspect of the present disclosure, there is
provided a system for controlling a turbocharger of a vehicle, the
system including: a plurality of turbochargers; a plurality of
wastegates respectively provided in the turbochargers and
controlling flow rates of exhaust gases passing through the
turbochargers; a plurality of opening ratio sensors provided on the
respective wastegates and measuring opening ratios of the
wastegates; a boost pressure sensor provided on an intake air flow
line at a location in a downstream of the plurality of
turbochargers and detecting a current boost pressure of intake air;
and a controller that sets a target boost pressure of intake air of
the plurality of turbochargers according to vehicle driving
conditions, sets target opening ratios of the plurality of
wastegates according to the target boost pressure, determines
whether or not a current opening ratio detected by an opening ratio
sensor of any one wastegate of the plurality of wastegates is lower
than the target opening ratio of the associated wastegate by a
reference value or less, limits a maximum rpm of the turbocharger
having the associated wastegate when it is determined that the
current opening ratio is lower than the target opening ratio by the
reference value.
As described above, the method and system for controlling a
turbocharger of a vehicle according to the present disclosure can
efficiently prevent breakage of the turbocharger caused by a
malfunction of a wastegate based on correct and efficient
determination of the malfunction of the wastegate.
Particularly, in a vehicle having a plurality of turbochargers and
a plurality of wastegates, the control method and system of the
present disclosure can correctly and efficiently determine a
malfunction of any one wastegate by determining whether or not the
difference between the current opening ratio and the target opening
ratio of the wastegate is equal to or greater than a reference
value.
Further, when the difference between the current opening ratio and
the reference opening ratio of the wastegate is equal to or greater
than the reference value, the control method and system of the
present disclosure limits the maximum rpm of the turbocharger
having the wastegate, thereby efficiently preventing breakage of
the turbocharger even when the wastegate of the turbocharger
malfunctions.
Further, in the control method and system of the present
disclosure, the reference numeral is pre-set in such a way that
reference values of the respective wastegates are determined in
consideration of the critical rpms of the turbochargers having the
respective wastegates, thus the control method and system can more
correctly and efficiently determine the malfunction of any one
wastegate, thereby efficiently preventing breakage of the
turbocharger having the wastegate.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and other advantages of the
present disclosure will be more clearly understood from the
following detailed description when taken in conjunction with the
accompanying drawings, in which:
FIG. 1 is a flowchart of a method of controlling a turbocharger of
a vehicle according to an exemplary embodiment of the present
disclosure; and
FIG. 2 is a view of a system for controlling a turbocharger of a
vehicle according to an exemplary embodiment of the present
disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
Exemplary embodiments of the present disclosure will be described
hereafter in detail with reference to the accompanying
drawings.
As shown in FIGS. 1 and 2, the method of controlling a turbocharger
of a vehicle according to an exemplary embodiment of the present
disclosure includes, in one embodiment: an opening ratio
determining step S100 of determining, by a controller 200, a target
boost pressure of intake air of a plurality of turbochargers 120
according to vehicle driving conditions, and determining target
opening ratios of a plurality of wastegates 180 respectively
provided in the plurality of turbochargers 120, according to the
target boost pressure; an opening ratio determining step S200 of
determining, by the controller 200, whether or not a current
opening ratio detected by an opening ratio sensor of any one
wastegate of the plurality of wastegates 180 is lower than the
target opening ratio of the associated wastegate 180 by a reference
value or less; and an overspeed rotation preventing step S300 of
limiting, by the controller 200, the maximum rpm of a turbocharger
120 having the associated wastegate 180 when it is determined that
the current opening ratio of the associated wastegate 180 is lower
than the target opening ratio by the reference value or less, and
preventing overspeed rotation of the turbocharger 120.
Described in detail, at the opening ratio determining step S100,
the controller 200 sets the target boost pressure of intake air
that is to be boosted by the plurality of turbochargers 120,
according to the vehicle driving conditions, and further sets the
target opening ratios of the wastegates 180 respectively provided
in the plurality of turbochargers 120, according to the pre-set
target boost pressure.
In the present disclosure, the plurality of turbochargers 120 is
provided to boost intake air. Here, the plurality of turbochargers
120 may be arranged in a serial manner or a parallel manner. In the
exemplary embodiment of FIG. 2, the plurality of turbochargers 120
are arranged in a parallel manner in which intake air boosted by
the respective turbochargers 120 is joined at the downstream of the
plurality of turbochargers 120 by a single flow line.
Here, the controller 200 sets the target boost pressure of intake
air of the turbochargers 120 according to the vehicle driving
conditions. Examples of the vehicle driving conditions, or
characteristics, may be a vehicle speed, a fuel injection amount, a
target torque, etc. The target boost pressure of intake air may
increase during high speed driving or quick acceleration of a
vehicle, and the rpm values of the turbochargers 120 are determined
depending on the target boost pressure of intake air of the
turbochargers 120.
Here, the relationship between the vehicle driving conditions and
the target boost pressure and the relationship between the target
boost pressure and the rotational speeds or the rpms of the
turbochargers 120 may be pre-set in the controller 200 or may be
determined using a data map stored in the controller 200. Further,
the relationships between respective variables may be variously
changed.
Further, since a plurality of turbochargers 120 are provided in the
present disclosure, the boost pressure of the plurality of
turbochargers 120 is mixed together in the single flow line of
intake air, thereby realizing the target boost pressure of the
total intake air.
In addition, although the rpms of the turbochargers 120 may be
controlled in various manners, the rpms of the turbochargers 120 in
the present disclosure are controlled by using the wastegates 180
that control the flow rates of exhaust gases passing through
respective turbines 122 of the turbochargers 120. In the present
disclosure, one wastegate 180 may be provided in each of the
turbochargers 120, so the number of wastegates 180 may be equal to
that of the plurality of turbochargers 120.
The wastegates 180 are provided on the respective bypass lines 150
of exhaust gases that pass through the respective turbines 122 of
the turbochargers 120. In the present disclosure, when a wastegate
180 is closed, all the exhaust gases flowing to an associated
turbocharger 120 pass through the turbine 122 of turbocharger 120,
so the rotational speed of the turbocharger 120 increases although
the vehicle is driven under the same driving conditions. On the
contrary, when a wastegate 180 is opened, the flow rate of exhaust
gases flowing to an associated turbocharger 120 is reduced, so the
rotational speed of the turbocharger 120 is reduced.
In other words, in the present disclosure, when the opening ratio
of a wastegate 180 increases, the rotational speed of an associated
turbocharger 120 having the wastegate 180 will be reduced. However,
when the opening ratio of a wastegate 180 is reduced, the
rotational speed of the turbocharger 120 having the wastegate 180
will increase. Due to the above-mentioned relationships, once the
target boost pressure is set, the controller 200 can determine the
rotational speeds of the respective turbochargers 120 capable of
realizing the target boost pressure. Further, the target opening
ratios of the wastegates 180 respectively provided in the
turbochargers 120 are individually determined according to the
rotational speeds of the respective turbochargers 120.
Further, at the opening ratio determining step S200, the controller
200 determines whether or not the current opening ratio detected by
an opening ratio sensor 185 of any one wastegate 180 of the
plurality of wastegates 180 is lower than the target opening ratio
thereof by the reference value or less.
In this case, the controller 200 compares the current opening
ratios of the plurality of wastegates 180 to the target opening
ratios thereof and analyzes the comparison results. Here, the
current opening ratios are the real opening ratios detected by the
opening ratio sensors 185 respectively provided to the wastegates
180.
When driving the turbochargers 120 having the respective wastegates
180, the current opening ratio of a wastegate 180 may fail to reach
the target opening ratio thereof because of various impurities
within exhaust gases adhered to the wastegate 180 or due to an
operational error of the wastegate 180.
For example, when a wastegate 180 fails to realize the target
opening ratio thereof due to impurities adhered thereto and the
current opening ratio of the wastegate 180 is higher than the
target opening ratio, the rotational speed of the turbocharger 120
having the wastegate 180 cannot reach a target value. Accordingly,
the current boost pressure in this case is lower than the target
boost pressure.
On the contrary, when the current opening ratio of the wastegate
180 is lower than the target opening ratio, the rotational speed of
the turbocharger 120 having the wastegate 180 increases over the
target value. When this condition further progresses, the rpm of
the turbocharger 120 exceeds the critical rpm, and this may cause
adverse conditions of the turbocharger 120.
The above-mentioned conditions act as important factors in the
present disclosure in which the plurality of turbochargers 120 are
provided. This is due to the fact that when the rpm of any one
turbocharger 120 is not appropriately controlled, the remaining
turbochargers 120 may fail to perform a desired operation.
For example, when the current opening ratio of the wastegate 180 of
any one turbocharger 120 is higher than the target opening ratio,
the rpm of the turbocharger 120 having the wastegate 180 is lower
than the target value.
Accordingly, when measuring a current boost pressure at the
downstream of the plurality of turbochargers 120, the measured
current boost pressure may be lower than the target boost pressure.
In this case, to increase the current boost pressure to the target
boost pressure, the opening ratios of the remaining turbochargers
120 may be controlled to be reduced, and thus the rotational speeds
of the turbochargers 120 may increase. In this case, the rotational
speed of a turbocharger 120 may increase to exceed a critical rpm,
and the turbocharger 120 may be not functioning properly.
However, when the malfunction of the boosting system using the
turbochargers 120 is checked based on the determination result of
whether or not the current boost pressure satisfies the target
boost pressure as described above, the following problem may occur.
That is, even when any one wastegate 180 malfunctions, the target
boost pressure of intake air may be realized, so the controller 200
may fail to recognize the malfunction of the wastegate 180. In this
case, the turbocharger 120 having the wastegate 180 may rotate at
an overspeed and may be suffer an adverse event.
Further, when the current opening ratio of the wastegate 180
provided in any one turbocharger 120 is lower than the target
opening ratio, the turbocharger 120 having the wastegate 180 may be
broken. In addition, the pressure or the flow rate of exhaust gases
flowing to the remaining turbochargers 120 in this case may
increase due to interference between, or the influence of, exhaust
gases.
Accordingly, when the current opening ratio of the wastegate 180 of
any one turbocharger 120 is lower than the target opening ratio
thereof, the rotational speeds of the remaining turbochargers 120
having respective wastegates 180 may increase, so breakage may be
propagated to all the turbochargers 120.
To solve this problem, in the present disclosure, the controller
200 compares the current opening ratios of the plurality of
wastegates 180 to the respective target opening ratios, and
determines whether or not any wastegate 180 of which the current
opening ratio is lower than the target opening ratio thereof by the
reference value or less is presented, thereby determining a
malfunction of the turbocharger 120 having the wastegate 180.
Further, when it is determined at the overspeed rotation preventing
step S300 that the current opening ratio of a wastegate 180 is
lower than the target opening ratio thereof by the reference value
or less, the controller 200 limits the maximum rpm of the
turbocharger 120 having the associated wastegate 180, thereby
preventing overspeed rotation of the turbocharger 120.
Described in detail, when the current opening ratio of any one
wastegate 180 is lower than the target opening ratio thereof by the
reference value or less, the turbocharger 120 having the associated
wastegate 180 rotates at an rpm exceeding the target rpm.
As described above, the method of checking the malfunction of the
turbochargers 120 by determining whether or not the current boost
pressure of intake air measured by the boost pressure sensor 190
satisfies the target boost pressure is problematic as follows. Even
when the rpm of any one turbocharger 120 exceeds the critical rpm,
the remaining turbochargers 120 may be maintained at low rpms, so
the controller may determine that the current boost pressure of
intake air satisfies the target boost pressure and may cause
breakage of the turbocharger 120 without recognizing the
malfunction of the turbocharger 120.
However, the present disclosure can correctly and efficiently
determine the malfunction of the wastegates 180 by checking the
opening ratios of the wastegates 180 respectively provided in the
plurality of turbochargers 120. When the current opening ratio of
any one wastegate 180 is lower than the target opening ratio
thereof by the reference value or less, the controller 200 of the
present disclosure limits the maximum rpm of the turbocharger 120
having the associated wastegate 180, thereby efficiently preventing
breakage of the turbocharger 120.
The reference value may be determined experimentally or
theoretically in various manners in view of improving control
strategy. Here, the reference value may be a deviation value that
is calculated experimentally or theoretically by using the target
opening ratio as a variable to reach a level capable of limiting
the maximum rpm of the turbocharger.
Further, the reference value may be determined in various manners
by those skilled in the art to provide a significant value capable
of preventing breakage of the turbochargers 120 while considering
the target opening ratios. For example, the reference value may be
determined in consideration of a safety factor in addition to the
above-mentioned factors.
Further, the limitation on the maximum rpms of the turbochargers
120 may be realized in various manners, for example, by a change in
the target opening ratio or in the target boost pressure. In other
words, in the present disclosure, when it is determined that a
wastegate 180 malfunctions, the maximum rpm of the turbocharger 120
having the wastegate 180 is limited and the turbocharger 120 may be
protected from breakage.
FIG. 1 is a flowchart of the method of controlling a turbocharger
of a vehicle according to the present disclosure, and FIG. 2 is a
view of the system for controlling a turbocharger of a vehicle
according to the present disclosure.
In the method of controlling the turbocharger of the vehicle
according to an exemplary embodiment of the present disclosure, the
reference value is pre-set for each of the plurality of wastegates
180 and is stored in the controller 200.
As described above, in the present disclosure, it is determined
whether or not any one wastegate 180 malfunctions. Here, due to the
difference between the design factors of the turbochargers 120, the
wastegates 180 of the turbochargers 120 may be broken at different
rpms.
Therefore, in the exemplary embodiment of the present disclosure,
the reference values used to prevent breakage of the wastegates 180
having respective target opening ratios are determined separately
for the respective wastegates 180, so the control method and system
of the present disclosure can more efficiently control the
respective turbochargers 120.
In other words, in the control method according to the embodiment
of the present disclosure, the reference values for the wastegates
180 are independently determined in consideration of critical rpms
of the turbochargers 120 having the respective wastegates 180.
Specifically, to determine the reference values used to prevent
breakage of the turbochargers 120 while considering the respective
target opening ratios, various methods may be used. In an
embodiment of the present disclosure, the reference values may be
determined in consideration of the critical rpms of the
turbochargers 120 having the wastegates 180.
Described in detail, the reference values for the plurality of
wastegates 180 may be determined in consideration of both the
target opening ratios of the wastegates 180 and the critical rpms
of the turbochargers 120 having the wastegates 180. In addition to
the above-mentioned method, the reference values for the plurality
of wastegates 180 may be determined by those skilled in the art in
various manners with the consideration of the critical rpms of the
turbochargers 120.
Briefly described, in an embodiment of the present disclosure, a
malfunction of the turbochargers 120 is checked based on design
factors of both the turbochargers 120 and the wastegates 180, so
the present disclosure can reduce the probability of making an
error in judgment and can efficiently prevent breakage of the
turbochargers 120.
Further, in the method of controlling a turbocharger of a vehicle
according to an embodiment of the present disclosure, when the
controller 200 determines, at the overspeed rotation preventing
step S300, that the current boost pressure of intake air is equal
to or lower than the target boost pressure and the current opening
ratio of the wastegate 180 is lower than the target opening ratio
by the reference value or less, the controller 200 limits the
maximum rpm of the turbocharger 120 having the wastegate 180 and
thus prevents overspeed rotation of the turbocharger 120.
In other words, when the current boost pressure of intake air
measured by the boost pressure sensor 190 at the downstream of the
plurality of turbochargers 120 is higher than the target boost
pressure, only the measurement of the boost pressure of intake air
may be used to efficiently check the probability of breakage of the
turbochargers 120.
The present disclosure is particularly effective in a condition
where the current boost pressure is equal to or lower than the
target boost pressure and it is impossible to check the probability
of breakage of the turbochargers 120 by comparison of the current
boost pressure to the target boost pressure.
Even when the rpm of any one turbocharger of the plurality of
turbochargers 120 changes because of the control for the
malfunction of the wastegate 180, the target boost pressure may be
realized due to the control for the rpms of the remaining
turbochargers 120, so the malfunction of the turbocharger 120 may
not be found.
To more efficiently determine the possibility of breakage of any
one turbocharger 120 in the above case, the present disclosure is
configured as follows, in some embodiments. That is, when the
current boost pressure is equal to or lower than the target boost
pressure and the current opening ratio of a wastegate 180 is lower
than the target opening ratio thereof by the reference value or
less, the controller 200 limits the maximum rpm of the turbocharger
120 having the wastegate 180, and thus efficiently prevents
breakage of the turbocharger 120.
Described in detail, in the method of controlling a turbocharger of
a vehicle according to an embodiment of the present disclosure, the
controller 200 limits, at the overspeed rotation preventing step
S300, the maximum rpm of at least one turbocharger 120 including
the turbocharger 120 having the wastegate 180 of which the current
opening ratio is lower than the target opening ratio by the
reference value or less.
When a plurality of turbochargers 120 like the present disclosure
are provided in a vehicle, the malfunction of any one turbocharger
120 may exert an adverse effect on the operation of remaining
turbochargers 120, and may cause breakage of the plurality of
turbochargers 120.
In other words, when the current opening ratio of the wastegate 180
of any one turbocharger 120 is equal to or higher than the target
opening ratio, the remaining turbochargers 120 may be controlled to
increase the rpms thereof and to realize the target boost pressure
according to vehicle driving conditions. In this case, the rpms of
the remaining turbochargers 120 may exceed the critical rpms. When
the current opening ratio of the wastegate 180 of any one
turbocharger 120 is equal to or lower than the target opening
ratio, the rotational speed of the turbocharger 120 adversely
increases and exhaust gases may not efficiently flow to the
turbocharger 120. Thus, the pressure or the flow rate of exhaust
gases flowing to the remaining turbochargers 120 in this case may
increase, thereby causing an increase in the rotational speeds of
the remaining turbochargers 120.
Accordingly, in an embodiment of the present disclosure, when it is
determined that the current opening ratio of the wastegate 180 of
any one turbocharger 120 is lower than the target opening ratio by
the reference value or less, the controller 200 limits the maximum
rpm of at least one turbocharger 120 including the turbocharger 120
having the wastegate 180 of which the current opening ratio is
lower than the target opening ratio by the reference value or
less.
Here, the limitation on the maximum rpm of the turbocharger 120 may
be realized in various manners, for example, by increasing the
target opening ratio of the wastegate 180, by limiting the output
power of an engine or by reducing the target boost pressure of
intake air.
Further, in the method of controlling a turbocharger of a vehicle
according to an embodiment of the present disclosure, the
controller 200 limits the maximum rpms of the turbochargers 120 by
limiting the target boost pressure at the overspeed rotation
preventing step S300.
In detail, the target opening ratios of the respective wastegates
180 are determined based on the target boost pressure of intake air
pre-set according to the vehicle driving conditions. Therefore, in
an embodiment of the present disclosure, the target opening ratios
of the wastegates 180 may be limited by limiting the target boost
pressure. Thus, it is possible to limit the maximum rpms of the
respective turbochargers 120 and this embodiment of the present
disclosure may be efficiently adapted to achieve a limitation on
the maximum rpm of at least one turbocharger 120.
In the method of controlling a turbocharger of a vehicle according
to an embodiment of the present disclosure, the controller 200
controls the plurality of wastegates 180 using a stored data map in
which the target opening ratios of the plurality of wastegates 180
are pre-set according to the target boost pressure of intake
air.
In other words, the controller 200 is stored with a data map in
which the target opening ratios of the respective wastegates 180
are pre-set according to a variation in the pre-set target boost
pressure of intake air. Due to the data map, the controller 200 can
quickly control the wastegates 180 without additionally performing
a calculation of the target boost pressure according to vehicle
driving conditions or a calculation of the target opening ratios of
the wastegates 180 according to the target boost pressure.
In addition, as shown in FIG. 2, the system for controlling a
turbocharger of a vehicle according to the present disclosure
includes, in some embodiments: a plurality of turbochargers 120; a
plurality of wastegates 180 respectively provided in the
turbochargers 120 and functioning to control the flow rates of
exhaust gases passing through the turbochargers 120; a plurality of
opening ratio sensors 185 provided to the respective wastegates 180
and functioning to measure the opening ratios of the wastegates
180; a boost pressure sensor 190 provided on an intake air flow
line 20 at a location in the downstream of the plurality of
turbochargers 120 and functioning to detect a current boost
pressure of intake air; and a controller 200 that sets a target
boost pressure of intake air of the plurality of turbochargers 120
according to vehicle driving conditions, sets target opening ratios
of the plurality of wastegates 180 according to the target boost
pressure, determines whether or not the current opening ratio
detected by an opening ratio sensor 185 of any one wastegate of the
plurality of wastegates 180 is lower than the target opening ratio
of the associated wastegate 180 by a reference value or less, and
limits the maximum rpm of the turbocharger 120 having the
associated wastegate 180 when it is determined that the current
opening ratio is lower than the target opening ratio by the
reference value or less, and thus prevents overspeed rotation of
the turbocharger 120.
Described in detail, in the present disclosure, a plurality of
turbochargers 120 is provided. In an exemplary embodiment of the
present disclosure shown in FIG. 2, two turbochargers 120 and two
exhaust gas lines 40 are provided. In the two exhaust gas lines 40,
respective turbines 122 of the two turbochargers 120 are
placed.
The turbochargers 120 may be arranged in a serial manner or a
parallel manner. In the exemplary embodiment of FIG. 2, the two
turbochargers 120 are arranged in a parallel manner. Here, two
intake air flow lines 20 are provided such that the intake air flow
lines 20 respectively passing through the two turbochargers 120 are
separated from each other. The two intake air flow lines 20 are
joined together at the downstream of the turbochargers 120 by a
single flow line.
Further, the wastegates 180 are provided in the plurality of
turbochargers 120, respectively. Thus, in the present disclosure,
the plurality of wastegates 180 is provided and functions to
control the flow rates of exhaust gases that pass through the
turbochargers 120 having the respective wastegates 180.
Specifically, in the present disclosure, bypass lines 150 are
provided to respectively bypass the turbines 122 of the
turbochargers 120, and the wastegates 180 are provided in the
respective bypass lines 150 to control the opening ratios of the
bypass lines 150.
Accordingly, as the opening ratios of the wastegates 180 increase,
the flow rates of exhaust gases that bypass the respective turbines
122 of the turbochargers 120 increase and the rpms of the
turbochargers 120 are reduced.
Further, the opening ratio sensors 185 are provided to the
plurality of wastegates 180, respectively, and function to measure
the opening ratios of the wastegates 180. Here, it is not necessary
to provide the opening ratio sensors 185 such that the opening
ratio sensors 185 are physically divided from each other according
to the respective wastegates 180, but it is sufficient that the
sensors 185 are provided to individually measure the opening ratios
of the wastegates 180. In the embodiment of FIG. 2, two opening
ratio sensors 185 are provided to be assigned to the two wastegates
180.
The boost pressure sensor 190 is provided on the intake air flow
line 20 at a location in the downstream of the plurality of
turbochargers 120 and functions to detect the current boost
pressure of intake air.
As described above, the boost pressure sensor 190 may be provided
on the intake air flow line 20 at the downstream of the plurality
of turbochargers 120 so that the boost pressure sensor 190 can
measure the current boost pressure of intake air boosted by the
plurality of turbochargers 120.
Accordingly, in the present disclosure, the current boost pressure
inside the intake air flow line 20 measured by the boost pressure
sensor 190 means the intake air boosting results performed by the
plurality of turbochargers 120.
Further, in the system, the controller 200 functions as follows in
some embodiments. The controller 200 sets the target boost pressure
of intake air of the plurality of turbochargers 120 according to
vehicle driving conditions, and sets the target opening ratios of
the plurality of wastegates 180 according to the target boost
pressure. The controller 200 also determines whether or not a
current opening ratio detected by an opening ratio sensor 185 of
any one wastegate of the plurality of wastegates 180 is lower than
the target opening ratio of the associated wastegate 180 by a
reference value or less, and limits the maximum rpm of the
turbocharger 120 having the associated wastegate 180 when it is
determined that the current opening ratio is lower than the target
opening ratio by the reference value or less. The controller 200
thus prevents an overspeed rotation of the turbocharger 120.
Therefore, even when a plurality of turbochargers 120 is provided
in a vehicle, the control system of the present disclosure can
correctly and efficiently determine the malfunction of any one
turbocharger 120, thereby efficiently preventing breakage of the
turbocharger 120.
Although an embodiment of the present disclosure has been described
for illustrative purposes, those skilled in the art will appreciate
that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the
disclosure as disclosed in the accompanying claims.
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